Effects of Enrofloxacin on Porcine Phagocytic Function

Abstract

The interaction between enrofloxacin and porcine phagocytes was studied with clinically relevant concentrations of enrofloxacin. Enrofloxacin accumulated in phagocytes, with cellular concentration/extracellular concentration ratios of 9 for polymorphonuclear leukocytes (PMNs) and 5 for alveolar macrophages (AMs). Cells with accumulated enrofloxacin brought into enrofloxacin-free medium released approximately 80% (AMs) to 90% (PMNs) of their enrofloxacin within the first 10 min, after which no further release was seen. Enrofloxacin affected neither the viability of PMNs and AMs nor the chemotaxis of PMNs at concentrations ranging from 0 to 10 g/ml. Enrofloxacin (0.5 g/ml) did not alter the capability of PMNs and AMs to phagocytize fluorescent microparticles or Actinobacillus pleuropneumoniae, Pasteurella multocida, and Staphylococcus aureus. Significant differences in intracellular killing were seen with enrofloxacin at 5؋ the MIC compared with that for controls not treated with enrofloxacin. PMNs killed all S. aureus isolates in 3 h with or without enrofloxacin. Intracellular S. aureus isolates in AMs were less susceptible than extracellular S. aureus isolates to the bactericidal effect of enrofloxacin. P. multocida was not phagocytosed by PMNs. AMs did not kill P. multocida, and similar intra-and extracellular reductions of P. multocida isolates by enrofloxacin were found. Intraphagocytic killing of A. pleuropneumoniae was significantly enhanced by enrofloxacin at 5؋ the MIC in both PMNs and AMs. AMs are very susceptible to the A. pleuropneumoniae cytotoxin. This suggests that in serologically naive pigs the enhancing effect of enrofloxacin on the bactericidal action of PMNs may have clinical relevance.

Preparation, characterization and pharmacokinetics of enrofloxacin-loaded solid lipid nanoparticles: Influences of fatty acids

“…A plasma concentration of 0.1 g/ml was considered therapeutically adequate, which is the MIC value of enrofloxacin against some common veterinary pathogens [36][37][38]. The long post-antibiotic effect of enrofloxacin can prevent bacterial re-growth even when plasma and tissue concentrations decrease below MIC [39]. The plasma enrofloxacin concentration in SLN groups maintained over the minimum therapeutic concentration for a long time and was below MIC for a persisted period, especially in the tetradecanoic acid-SLN and palmitic acid-SLN groups.…”

Responses of pigs to a re‐challenge with Actinobacillus pleuropneumoniae after being treated with different antimicrobials following their initial exposure

“…This effect may help to explain why the pigs treated with enrofloxacin did not seroconvert. It has also been shown that the killing of A pleuropneumoniae by alveolar macrophages and polymorphonuclear leucocytes is enhanced by enrofloxacin (Schoevers and others 1999). …”

The influence of antibiotics on B-cell number, percentage, and distribution in the bursa of Fabricius of newly hatched chicks

“…on humoral immunity in humans has been reported after ciprofloxacin treatment (Williams et al, 2005). However, enrofloxacin may lead to an increase in the bactericidal action of phagocytes, such as neutrophils, in pigs (Schoevers et al, 1999). It has also been shown that after enrofloxacin administration the number of lymphocytes in the peripheral blood of 17-d-old chickens was significantly higher than that in the control group (Fleischer et al, 2000).…”